[TRNSYS-users] Type 64 and 67 shading mask

David BRADLEY d.bradley at tess-inc.com
Fri Jun 12 12:50:54 PDT 2015


Marcello,
   You are correct about the file; the surface angles correspond to 
absolute azimuths and are not relative to the opening. That should teach 
me to check the documentation one more time before sending out advice!
best,
  David


On 06/12/2015 02:11, marcello.caciolo at cofelyaxima-gdfsuez.com wrote:
>
> Dear David,
>
> Thank you for your answer. I think that I am going to use type 67 
> only, following your advice.
>
> However, I have a doubt about what you say in your answer :
>
> /“if you have more than one orientation to worry about then you can 
> just shift the horizon index for each different orientation of in the 
> file. The angular heights of obstructions don't change; only their 
> position on the horizon changes.”/
>
> //
>
> //However, from the TRNSYS manual : “/The surface angles for which 
> angular obstruction heights are provided correspond to absolute 
> azimuths; they are NOT specified relative to the azimuth of the opening”./
>
> I understand from this that -180 corresponds always to North (for our 
> Hemisphere), -90 to East , 0 to South and 90 to West, whatever the 
> surface azimuth is. Thus, I can just past and copy the same profile 
> for each opening, right? There should be no need to change the 
> position on the horizon.
>
> Thank you for your attention.
>
> Best regards,
>
> *Marcello Caciolo*
> Responsable Outils et Méthodes d'Analyse Energétique
>
> cid:image003.jpg at 01CD4E08.954D04D0
> *
> *Cellule Efficacité Energétique et Environnementale
>
> INGÉNIERIE PROJETS
> 15 rue Nina Simone
> CS 39601 - 44096 Nantes cedex 1
> Tél.: +33 02 40 41 06 57
> marcello.caciolo at cofelyaxima-gdfsuez.com 
> <mailto:prenom.nom at aximaseitha-gdfsuez.com>
>
> *Le 26 mai 2015, nous emménageons au 15 rue Nina Simone – CS 39601 – 
> 44096 Nantes cedex 1*
>
> *Nos numéros de téléphone restent inchangés*
>
> *De :*David BRADLEY [mailto:d.bradley at tess-inc.com]
> *Envoyé :* jeudi 11 juin 2015 22:11
> *À :* TRNSYS users mailing list at OneBuilding.org; Caciolo Marcello 
> (Axima Concept)
> *Objet :* Re: [TRNSYS-users] Type 64 and 67 shading mask
>
> Marcello,
>   I'm not sure how one might combine Types64 and 67. Despite the fact 
> that I wrote Type64, I have never been convinced that it was a very 
> useful model. It computes the impact of a faraway mask on radiation 
> falling on a horizontal surface and was intended to be a "quick and 
> dirty" model to get a basic idea of shading by applying one mask to 
> all surfaces regardless of their orientation. If you want a correct 
> estimation of shading by obstacles (whether they are far off or 
> nearby) then you should really use Type67 in order to be correct in 
> the estimation of how the horizon affects that surface. The 
> disadvantage of Type67 of course is that you need to provide a mask 
> for each surface. However, all the masks can be provided in a single 
> file and if you have more than one orientation to worry about then you 
> can just shift the horizon index for each different orientation of in 
> the file. The angular heights of obstructions don't change; only their 
> position on the horizon changes.
> best,
>  David
>
> On 06/11/2015 02:25, marcello.caciolo at cofelyaxima-gdfsuez.com 
> <mailto:marcello.caciolo at cofelyaxima-gdfsuez.com> wrote:
>
>     Dear Trnsys users,
>
>     I have a question about the possibility to use type 64 and type 67
>     together.
>
>     In my projects, I use to define a “geographical” horizon line,
>     valid for all orientations, by type 64, and to use type 67 for
>     masks due to near obstacles (trees, buildings, …) (different for
>     each surface). Self-shading from overhang and wingwall are taken
>     into account by type 34.
>
>     Then, I connect outputs of type 64 to  type 67 and outputs of type
>     67 to type 34.
>
>     However, type 34 provide a parameter to say if radiation is
>     provided by type 64 or 67, in order to avoid to take into account
>     twice the sky view factor, but type 67 does not.
>
>     I wonder if this can have an impact on results.
>
>     Could you please give me your advice?
>
>     Thank you!
>
>     Best regards,
>
>     *Marcello Caciolo*
>     Responsable Outils et Méthodes d'Analyse Energétique
>
>     cid:image003.jpg at 01CD4E08.954D04D0
>     *
>     *Cellule Efficacité Energétique et Environnementale
>
>     INGÉNIERIE PROJETS
>     15 rue Nina Simone
>     CS 39601 - 44096 Nantes cedex 1
>     Tél.: +33 02 40 41 06 57
>     marcello.caciolo at cofelyaxima-gdfsuez.com
>     <mailto:prenom.nom at aximaseitha-gdfsuez.com>
>
>     *Le 26 mai 2015, nous emménageons au 15 rue Nina Simone – CS 39601
>     – 44096 Nantes cedex 1*
>
>     *Nos numéros de téléphone restent inchangés*
>
>
>
>
>     _______________________________________________
>
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>
>     TRNSYS-users at lists.onebuilding.org  <mailto:TRNSYS-users at lists.onebuilding.org>
>
>     http://lists.onebuilding.org/listinfo.cgi/trnsys-users-onebuilding.org
>
>
>
> -- 
> ***************************
> David BRADLEY
> Principal
> Thermal Energy Systems Specialists, LLC
> 22 North Carroll Street - suite 370
> Madison, WI  53703 USA
>   
> P:+1.608.274.2577
> F:+1.608.278.1475
> d.bradley at tess-inc.com  <mailto:d.bradley at tess-inc.com>
>   
> http://www.tess-inc.com
> http://www.trnsys.com

-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI  53703 USA

P:+1.608.274.2577
F:+1.608.278.1475
d.bradley at tess-inc.com

http://www.tess-inc.com
http://www.trnsys.com

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